<!-- z-index 900 to keep error overlay on top of chart controls (which are at z-index 800),
 but below date and navbar dropdown (which are at z-index 1000) -->
<div class="gt-panel-overlay" ng-if="httpError" style="z-index: 900;">
  <div ng-include src="'template/gt-http-error.html'"></div>
</div>
